Built in the early 1950s and designed by famed architect Eero Saarinen, the 330-acre Technical Center is home to a design center, engineering facilities, and manufacturing centers.



While it does seem like a cool place to visit, GM also has a super strict policy which prevents visitors from taking snapshots of the premises.

This was discovered by Will Wei and Alex Davies of Business Insider, who had an opportunity to visit the top secret center while attending the 2014 Detroit Auto Show.



The process involves checking in any recording devices with the security guards at the entrance, who will then cover them up with these stickers.



What's special about these stickers is that they can change color once peeled off. This ensures that visitors don't sneakily take the sticker off, snap some shots, before sticking it back on.